System for exhausting container



Jan. 5, 1965 E. GUTTER SYSTEM FOR EXHAUSTING CONTAINER 5 Sheets-Sheet 1 Filed Oct. 26. 1961 I III I 1/ 1/] III 441- A/A-I/ IN V EN TOR. ERNST GUTTER Jan. 5, 1965 E. GUTTER SYSTEM FOR EXHAUSTING CONTAINER 3 Sheets-Sheet 2 Filed Oct. 26, 1961 .Fiyz

IN VEN T 0R. ERNST GUTTER BY f? Jan. 5, 1965 E. GUTTER 3,164,170

SYSTEM FOR EXHAUSTING CONTAINER Filed Oct. 26, 1961 s Sheets-Sheet .3

IN V EN TOR.

ERNST CUTTER I is coupled to the chamber by a valved connection.

United States Patent s Ciaims. (i.137567) This invention relates to a valve system for evacuation equipment and, more particularly, relates to such a system in which provision is made for sequence operation of valves in such manner as to preclude improper operation.

In conventional evacuation systems, the container to be evacuated is coupled to a low vacuum pump to quickly evacuate the container to a desired initial vacuum. When the desired initial vacuum is reached, the container is coupled to a high vacuum pump, such as a diffusion pump, to reach the desired final vacuum. The difiusion pump may be pre-evacuated by an independent vacuum pump or by the same pump as used for the pre-evacuation of the chamber. v

In the systems known to the art, the high vacuum pump The pre-evacuation pump is coupled to the chamber by a bypass valved connection.

However, since it is necessary to prevent the admission of air into the hot diifusion pump, it is necessary to provide valve interlocks, either of mechanical or electrical nature, to ensure that the valves can be opened only in the proper sequence. These systems are unduly complex and expensive.

. It is, therefore, the primary object of this invention to provide a valve system having alternatively acting valves.

In accordance with this object, there is provided, in a preferred embodiment of this invention, a valve system comprising a cylinder which is closed at one end and coupled to the chamber to be evacuated at the other end. Three spaced annular bushings or packing glands are provided in the cylinder. An open tube constitutes the piston which is reciprocally mounted within the bushings, in vacuum-tight relationship.

A first and second vacuum line to the cylinder into the spaces defined respectively by the three spaced bushings is provided. The high vacuum pump may be coupled to one line and the pre-evacuation pump coupled to the other line. Reciprocation of the tubular piston from a rest position in which both lines are closed by the engagement of the piston wall with all bushings, will first open the line to the pre-evacuation pump and then simultaneously close the pre-evacuation pump and open the line to the high vacuum pump.

Means are provided to prevent improper sequence of this valve system in simple and expedient fashion. The valve system proper is both simple and is not subject to breakdown. 1

Further, it is possible to easily adapt the valve system to the flow conditions of the application intended merely by proper position of the relative distance between the annular bushings.

' It may be. advantageous to provide a mechanical device piston, said rod being supported eccentrically on a ratchet Wheel which is movable only in one direction of rotation. In order to be able to construct the new valve system "ice I It has been found advantageous in'many applications I to control the reciprocation cycle of the piston by vacuum sensors so that the cycle is automatically related to evacuation of the chamber. The reciprocation cycle may, of course, be predetermined by limit switch control over piston drive with initiation of the cycle controlled manual- Itfis advantageous to couple the pressureside of the high vacuum pump to the suction line of the low vacuum pump through a selectably operable valve. This valve is preferably actuated automatically in response to the piston cycle so that the coupling is made only when the coupling between the low vacuum pump and the cylinder is closed.

Having briefly described the invention, it will be described in detail, along with additional objects and advantages thereof, in the following description in conjunction with the accompanying drawings, of which:

FIG. 1 is a schematic diagram of the valve system in accordance with the present invention;

FIG. 2 is a cross section through an industrial embodiment of the new valve system, in which the sliding tube is moved via an electric motor; V

FIG. 3 is a top view of the valve systemshown in FIG. 2; 1

FIG. 4 is a schematic showing of the new valve system and of the vacuum pumps connected 'to this system; and

FIG. 5 shows a wiring diagram for the automatic actuation of the tube displacement as a function of the vacuums obtained. I

Referring to FIG. 1, there is shown apump system in accordance with the present invention'which comprises a cylindrical housing or cylinder 1, said cylinder being closed at one end and communicating with a chamber 8. In the housing 1, there are provided three packing rings 2, 3, and 4 which are arranged stationary and vacuumtight within the housing. The packings are preferably in the form of lip or circular cord packings. The piston 5 is an open ended tube which is slidably mounted in these packing rings or glands.

The cylinder 1 is provided with two lateral connecting lines 6 and 7 which enter into the cylinder, 1 between the packingrings 2 and 3, and 3 and 4 respectively. In the position shown, the connecting line 6 is isolated from the chamber 3 by the wall of the piston 5 and the glands 2 and 3. The connecting line .7 is isolated from the chamher 8 by the contact between the wall of piston 5 and the glandsS and 4.

If the valve system shown in FIG. 1 is used in a vacuum installation, the chamber 8 represents the container, the high vacuum pump is connected to the connecting line 6 and the pre-vacuum or low vacuum pump is connected to the connecting line 7. Forcarrying out the pumping/it is necessary that the line 7 be connected with the chamber 8 initially and then, with simultaneous closure of thecbnnecting line 7, the connection be made between the 'conrotation in' the direction indicated by the arrow is made possible over the circumferential portion of the wheel 9 provided with teeth. A connecting'rod 11 isarranged eccentrically to the ratchet wheel 9 and pivoted to a slide in a small space and to provide the possibility of cornpletely automatic control, it is advantageous to provide an electric motor and control network to displace the piston in a reciprocation cycle to sequentially couple the vacuum lines to the respective pumps as desired.v

rod 13. The slide rod 13 is linearly guided inthe sleeve 12 and is connected via a vacuum-tight packing glandin thehousing 1 witha disc 14 which [is rigidly connected to the tubular wall of the piston-5. The'disc '14 is provided with one or more apertures 15 which permit the passage of gas.

The manner of operation of the valve system shown here is as follows. If the ratchet Wheel 9 is turned in the It consists of the ratchet wheel 9 which co-v direction indicated by'the arrow, the sliding tube moves to the left and finally reaches the position indicated in dotted line. In this position the pre-vacuum pump is connected with the container while the main vacuum pump is isolated from the container. It is possible to move back from this pre-evacuationposition into the rest position in order to be able to correct any possible malfunction in the system and vacuum chamber. For this purpose, the corresponding circumferential region of the ratchet wheel 9 is not provided with teeth. 7

After reaching the predetermined pre-vacuum, the ratchet wheel 9 is turned further in the direction indicated by the arrow. As a result of this, the sliding tube 5 first of all moves back into the rest position and then towards the right up to the position shown till dotted line. In this position the main or high vacuum pump, is connected with the container while the pre-vacuum pump is disconnected.

If the container is now to be vented, the ratchet wheel 9 is turned in the directzion indicated by the arrow up to the rest position shown in FIG. 1. When this position has been reached, the container can be vented without the vacuum in the pump lines being disturbed. For the venting of thecontainer there can be provided a solenoid valve which is normally closed and is provided with such an interlocking device that it can be opened only in the rest position of the sliding tube 5.

By the provision of-cam discs on the ratchet wheel 9, electric contacts which control still other valves can be actuated. Thus, for instance, when using only one prevacuum pump, the suction line of said pump is connected with the pressure line of the main vacuum pump. In the'connecting line there is provided a solenoid valve which in normally opened condition provides communication between the two pumps and is closed by a cam-controlled s'witch only as long as the by-pass valve is open.

In the case of the embodiment of the valve system shown in FIG. 2, the piston 5 is driven via an electric motor 16 which drives a gear 18 via a gearing 17. With the gear 13 there is engaged another gear 19, the shaft of which is passed hermetically through the housing 1 and is connected with a threaded spindle 20. This spindle is supported in a nut which is rigidly mounted on the disc 21 coupled rigidly to the annular Wall of piston 5. The

disc is provided with one or more apertures 22 serving for the passage of air. This disc also contains a bore hole through which there ispassed a rod 23 to secure the sliding tube 5 against rotation. Thisrod is supported in fixed position in the housing 1.

Corresponding to the direction of rotation of the electnic motor 16 the sliding tube will therefore be moved towards the left or towards the right. During this movement, the pre-vacuum pump, connected via the line 7, and .thehigh vacuum pump, connected via the line 6, will be connected alternately, one after the. other, with a the container 8.

The electric motor 16 via the gearing 17 describes an other threaded spindle 24 which is arranged above the housing 1 and on which there is arranged a threaded nut 25 which is secured against rotation. This threaded nut is provided with a projection 26. Limit switches 27, 23 and 29 are provided to which are respectivelytripped when thepiston 5 is in the rest position as shown in FIG.

2, the position at which the connection between the pre- I The operation of the switches will be described in the the threaded nut 25 as it moves towards the right.

d of the pro-vacuum pump 33 there is furthermore connected a known vacuum switch box 34. This vacuum switch box contains contacts which open when a predetermined vacuum is reached.

The manner of operation of the valve system shown in FIGS. 2 to 4 is as follows. When actuated, the two pumps 32 and 33 start to operate, whereby the valve 31 is open. After reaching a sufficiently good pre-vacuum in the pump lines, including the high vacuum pump, the piston 5 is shifted to the left via the electric motor 16. In this connection the limit switch 28 returns to its rest position and the electric motor continues to run until the limit switch Ed is actuated by the projection 26 of Upon the actuation of this limit switch, the electric motor 16 is disconnected. The sliding tube has thereby reached the first switch position, i.e. the connection is made between the pre-vacuum pump 33 and the container 8.

During the displacement of the piston 5 to the first switch position, the switch 30 is closed via the threaded nut as a result of which the valve 31 closes before the opening of the connection between the connecting lines 7 and the container 3 and interrupts the connection between the pre-vacuum pump 33 and the main vacuum pump 32. After reaching the prescribed pre-vacuum, the electric motor 16 is connected in the other direction of rotation. As a result of this, the sliding tube 5 moves to the second switch position at which the main vacuum pump 32 is connected with the container 8. At the same time, the threaded nut 25 moves towards the left, it being seen to it that the actuation of the limit switch 28 taking place upon passage of the sliding tube 5 through the rest position does not disconnect the motor 16. The motor is only disconnected when the limit switch 27 is actuated via the projection 26.

During the shifting of the sliding tube 5 from the first switch position into the second, and shortly before the sliding tube reaches the rest position, the switch 3t; opens as a result of which the solenoid valve 31 is opened. As

4 pump 33.

tion.

if finally the container 8 is to be vented, the electric motor in is again connected and now displaces the sliding tube 5 from the second switch position into the rest posi- After this position is reached, the limit switch 23 is actuated and disconnects the electric motor 16.

FIG. 5 shows a circuit in which the electric motor 16 is automatically connected via the vacuum switch box 34 after the predetermined vacuum has been reached and in which the limit switches 27, 28 and 29 shown in FIG. 3 serve to disconnect the electric motor. This circuit consists of the actual control device 35 acted upon by the vacuum switch box 3-4 and the other circuit containing the connecting and disconnecting switches for the electric motor 16 and the corresponding other switch members.

The switch device 35 contains two cold cathode tubes 36 and'37, connected with direct voltage which effects the connecting of the electric motor 16 and a cold cathode tube 38 connected to alternating voltage, which after reach ing the high vacuum value measured above. the prevacuum of the main vacuum pump, releases switching processes which are dependent upon said value. The

switches 391, 392 and 3% are actated via a relay 39 by the threaded nut 25. It, on the other hand, a limit switch, for instance 23 in FIG. 2, is contacted by the threaded nut 25 then this switch is said to be actuated.

The manner of operation of the circuit shown in FIG. 5 is as follows. After a direct voltage has been applied to the contacts 42 and 43, the switch 41 is closed. The starter electrode 361 of the cold cathode tube 36 is grounded via the switch 44 of the vacuum switch box 34. For this reason the tube 36 does not at first ignite. The piston 5 is in the rest position and the pre-vacuum pump 33 evacuates the high vacuum pump. As soon as the adjusted value of the pro-vacuum has been reached in the pump lines, the switch 44% of the vacuum switch box 34 opens. At this moment, the starter electrode 361 receives the ignition voltage via the resistors 45 and 45 so that the cold cathode tube 36 ignites. In this connection the relay 39 is attracted and actuates the switches 391, 392 and 393 from the rest position shown in the drawing. By the reversing of the switch 393 to contact a, a current flows through the relay 47 which actuates the switches 471 and 472. Furthermore, a current flows through the limit switch 27 which is in rest position, the switch 392 lying at the contact c and the limit switch 29 located in rest position via the switch 471 connected to the contact through the electric motor 16. By the position of the switch 471, it is made certain that the electric motor 16 starts up in the proper direction of rotation and in this connection moves the piston 5 in the direction towards the first switch position. After reaching the first switch position, the limit switch 29 is actuated and interrupts the supply of current to the electric motor 16.

Upon the igniting of the cold cathode tube 36 the switch 7 391 is moved to the contact g and the charging current of the capacitor flows over the resistors 45, 4t; and 49. The voltage at the start of 371 of tube 37 increases only so slowly that the ignition voltage is reached only after about 30 seconds. If now, however, the piston 5 is moved, out of the rest position into the first switch position, the vacuum into the suction line 7 is impaired and the switch 44 of the vacuum switch box-34- closes after less than 30 seconds. As a result of this, the capacitor $6 discharges over the switches 391 and '44, and the tube 37 does not ignite. The tube 36 on the other hand continues to burn although its starter 361 is again grounded. This, as is known, is a characteristic of cold cathode tubes operated with direct voltage.

After the piston 5 is in thefirst switch position, the container 8 is pre-evacuated via the pro-vacuum pump 33. As soon as the adjusted value of the pre-vacuum has been reached the contact 443 of the vacuum switch box opens again. The capacitor now charges itself up to ignition voltage at the starter electrode 371 and the cold cathode tube 37 ignites. In this connection the switch 4% is opened via the relay and the-tube 36 is thereby put out. At the same time, the relays-ti actuates the switches 4192 and M3 from the rest position shown in PEG. 5. This has the result first ofwall that the switches 392 and 3% shown in the drawing. A current now flows over the piston 5 out of the first switch position. When the piston 5 has reached the rest position, the limit switch 28 is actu ated. In this position the current flow through 27, 392, 512 and 471 back through the electric motor 16, i.e. the electric motor is therefore not disconnected. Only after the second switch position of the piston is reached is the limit switch 27 actuated and thus interrupts the current supplied to the electric motor 16.

The high vacuum pump 32 is now connected with the container 8 and evacuates it to the prescribed value of high vacuum. When this value has been reached, the switch 52 of the vacuum switch box 34 opens and the ignition voltage passes via the resistor 53 to the starter electrode 381 of the cold cathode tube 38 connected to alternating voltage. This tube ignites and the switch 541 is closed via the relay 54. In this way current flows over the actuated limit switch 27 and the closed switch 541 through the indicating bulb and the closed switch 432. The bulb 55 therefore lights up and indicates that the prescribed high Vacuum value has been reached.

Relay 54 serves, if the container 8 is an electron microscope, at the same time to actuate a switch (not shown in the drawing) which connects the high voltage. Similarly, the relay 54 can also release additional switching.

processeswhich depend upon the. reaching of the high vacuum value.

If the vacuum value in the container 8 becomes worse due to any defect, the switch 52 immediately closes. In this way the starter electrode 381 is grounded and the cold cathode tube 33 will go out upon the next passage of the anode alternating voltagethrough zero. In this connection the relay 54 also drops out and disconnects for instance the high voltage.

For the normal disconnecting of the apparatus, the switch 41 is opened. In this way the cold cathode tube 37 is put out and. switches 492 and 403 return into the rest'position shown in the drawing. Inthis connection the switches 392 and 393 also remain in the rest position actuated limit switch 27, the closed switch 403, and the switch 393 lying at contact 12, through the relay 47. By this relay the switches 471 and 472 are actuated so that therefore the direction of rotation of the electric motor 16 is again reversed. The motor 16 receives current via the actuated limit'swtich 27, the closed switch 472 and the switch 471 connected with the contact fand thereby" limit switch 23 is actuated, i.e. it assumes the switch posimove back again into the rest position shown'in the drawing. In this connection the relay 47' drop out and the switch 4'71 moves onto the contact e. 1

A current now flows over the limit switch 27. which is still inrest position, the switch 3%2 which is at the contact 0 and the limit switch 28 which i in rest position through I 3&2, over the limit switch 28 which has returned to the rest position, and over the actuated limit switch 2? through the relay 511 and the closed switch it? The relay actuates the switches 511i, 512 and 513. The. relay 51 is maintained energized by the closed switch 511 ,evenaften the return of the limit switch 29 into the rest position, i.e. therefore after the commencement of the movement of the tion shown in the drawing and interrupts the supply of current to the electric motor 16.

Inordier that when the limit switch 27 jumps from its limit position into therest position shown in the drawing the relay 47 does not drop out, the limit switch 27 is formed of two switches connected in parallel. These two parallel switches have somewhat different switching times so that the switching gap is bridged over. As can be noted from FIG. 2, the two limit switches 27 are preferably arranged one above the other. i

1 A feeler 56 serves tovent the container. When this feeler-is actuated, relay 57 is attracted and opens the vent valve-(not shown). Therelay 57 also actuatesa switch 571 so that it is held'energized even'aftcr release of the feeler 56. The feeler 55 can only actuate the relay 57 in the rest position shown inFIG. 5. If one fromthe first switch position to thesecondQtheswitch 513 will ,be opened via therelay 51- actuated in this position and the' relay 57 will not receive any current,

'der' being closed; the other end of said cylinder I con'd positionfrom its first position.

If, on the other hand, the switch 56 is actuated in the rest position of the piston 5, the switch 513 is closed and the relay 57 is attracted. This relay now holds itself energized until the piston again comes into the first switch position and the limit switch 58 thereby returns into its rest position.

'The'electric circuit shown in FlG. 5 prevents improper operation of the valve. The piston 5 can only be brought into the second switch position after it has reached the end position of'the first switch position.

if automation of: the movement of the sliding tube is not to be obtained,'then the circuit arrangement shown in FIG. 5 is omitted. In this case, the mechanically interconnected switches 392 and 393 must be actuated in order to connect the valve system. After reaching the first switch position the electric motor 16 is disconnected and moves into the second switch position, only when after suitable pre-vacuum measurement, the switches 4m and 403, which are coupled to each other, are actuated. In this connection the switches 392, 393 or 4%, 403 respectively shall operate only alternately, i.e. aside from the rest position of all switches shown in PEG. 5, in each case only the switch 392, 393 or the switch 492, 403 maybe in connected position. Such a switch combination can be achieved for example by slide or push buttons'orby-a four pole rotary switch with three switch positions. 7 w v This invention may be variously embodied and modified within the scope of the subjoined claims.

What is claimed is:

' 1. A valve system having two alternately acting valves, comprising a cylindrical housing, one end of said cylinsing in communication with the container of a vacuum installation, a first, second and third annular packing giand positioned in said cylinder at spaced locations therein, .a first and second'connecting lineprespectively coupled between said first and second and said second and third glands, a high vacuum and a pre-vacuum pump coupled respectively to said first and second connecting lines, a piston, said piston being open on both ends and recip rocally mounted in said glands and being of sufficient length to sealingly contact all of the glands simultaneously when infa rest position, and reciprocating means operatively connected to said piston to: displace said piston in'a reciprocation cycle from the rest position in which said piston'contacts all glands thereby closing said two connecting lines into a first position in which said piston contactsonly said first and second glands thereby opening the connection between said pro-vacuum pump and said container and then into the second position in which said pistonrcontacts said second and third glands thereby opening the connection between said high vacuum pump and said container.

2. A valve system according to claim 1 in which said reciprocating means comprises an electric motor, gear means coupled to said motor and said piston to displace said piston when saidelectric motor is rotated, limit switches; means coacting with said piston for operating said limit switches in the rest position and in the first and second position of the'valve, circuit means with the limit 0 rest position, and means responsive to a predetermined vacuum in the pre-vacuum pump connection for reversing the motor and restarting it to move said piston to its sec 3.. A valve system according to claim 2 in which the pressure side of the high vacuum pump is connected in this connection, a vacuum switch box connected with the suction line of the pre-vacuum pump, said switch box containing a contact which is opened after a predetermined vacuum value is reached in said suction line, a first relay energized by the opening of said contact for starting said electric motor to move said piston from the rest position into the first position, a second relay energized by the opening of said contact of the vacuum switch box after said piston is in the first position to start said electric motor to move said piston from the first into the second position.

4. A valve system according to claim 3 in which said vacuum switch box contains a second contact which is opened after the high vacuum value is reached, a third relay energized by the opening of said second contact to indicate reaching said high vacuum value.

5. A valve system according to claim 4 which includes a first gas discharge tube connected to direct voltage which 3 ignites upon the placing in operation of the valve system after reaching the predetermined pro-vacuum value in the main vacuum pump, a first relay tripped by ignition of said first gas discharge tube to energize the electric motor to displace the piston into said first position, and a second gas discharge tube connected to the same direct voltage and which, after reaching the predetermined vacuum value in the container, ignites and a second relay tripped by ignition of sai' second gas discharge tube to energize the electric motor for shifting the piston into the second switch position and simultaneously to disconnect the anode volt age of the first gas discharge tube.

6. A valve system according to claim 3 further compris ing a switch, means coacting with said piston for operating 7 said switch when said piston is moved from its rest position into the first position and from the'second position back to the rest position, circuit means arranged with said switch to close said valve as long as there is a connection between said vacuum container and the pre-vacuum con 9 nection.

7. A valve system according to claim 6 characterized by the fact that the control electrode of the first gas discharge tube is grounded via a contact of the vacuum switch box, g which contact opens when the predetermined vacuum value is reached, and upon the opening of this contact is connected to the positive'ignition voltage, and that upon the ignition of this gas discharge tube, the ignition voltage is fed via a time delayng member to the control electrode of the second gas discharge tube.

8. A valve system according to claim 1 characterized by such a development of a time delay member that the ignition voltage reaches the control electrode of the second gas discharge tube only after about seconds.

References Cited by the Examiner UNiTED STATES PATENTS 669,284 r 3/01 Pelton 137-62558 1,105,090 7/14 Metzger 137625.4 2,522,969 9/50' Smith 3l5--107 I 2,707,249 4/55 Schneider 137 566 XR 2,843,150 7/58 Goodwin 137-625 XR 3,007,496 11/61 Heiss 137627.5

ISADQR WEIL, Primary Examiner.

WrLLrA F. ODEA, Examiner. 

1. A VALVE SYSTEM HAVING TWO ALTERNATELY ACTING VALVES, COMPRISING A CYLINDRICAL HOUSING, ONE END OF SAID CYLINDER BEING CLOSED, THE OTHER END OF SAID CYLINDER BEING IN COMMUNICATION WITH THE CONTAINER OF A VACUUM INSTALLATION, A FIRST, SECOND AND THRID ANNULAR PACKING GLAND POSITIONED IN SAID CYLINDER AT SPACED LOCATIONS THEREIN, A FIRST AND SECOND CONNECTING LINE RESPECTIVELY COUPLED BETWEEN SAID FIRST AND SECOND AND SAID SECOND AND THRID GLANDS, A HIGH VACUUM AND A PRE-VACUUM PUMP COUPLED RESPECTIVELY TO SAID FIRST AND SECOND CONNECTING LINES, A PISTON, SAID PISTON BEING OPEN ON BOTH ENDS AND RECIPROCALLY MOUNTED IN SAID GLANDS AND BEING OF SUFFICIENT LENGTH TO SEALINGLY CONTACT ALL OF THE GLANDS SIMULTANEOUSLY WHEN IN A REST POSITION, AND RECIPROCATING MEANS OPERATIVELY CONNECTED TO SAID PISTON TO DISPLACE SAID PISTON IN A RECIPROCATION CYCLE FROM THE REST POSITION IN WHICH SAID PISTON CONTACTS ALL GLANDS THEREBY CLOSING SAID TWO CONNECTING LINES INTO A FIRST POSITION IN WHICH SAID PISTON CONTACTS ONLY SAID FIRST AND SECOND GLANDS THEREBY OPENING THE CONNECTION BETWEEN SAID PRE-VACUUM PUMP AND SAID CONTAINER AND THEN INTO THE SECOND POSITION IN WHICH SAID PISTON CONTACTS SAID SECOND AND THIRD GLANDS THEREBY OPENING THE CONNECTION BETWEEN SAID HIGH VACUUM PUMP AND SAID CONTAINER. 